Drop on demand ink jet technology is widely used in the printing industry. Various types of technology may be used to implement drop on demand ink jet printing. One of the more common technologies utilizes printheads with piezoelectric ink jets.
Piezoelectric ink jet printheads typically include a flexible diaphragm, contained within a jetstack body, and an array of transducers, i.e., piezoelectric elements, attached to the diaphragm. When a voltage is applied to a transducer, typically through electrical connection with an electrode electrically coupled to a voltage source, the transducer bends or deflects, causing the diaphragm to flex which expels a quantity of ink from a chamber through a nozzle. The flexing further draws ink into the chamber from a main ink reservoir through an opening to replace the expelled ink.
The electrode, described above, typically protrudes as a pad electrode from a flexible printed circuit and is typically electrically connected to the transducer via a conductive material such as a silver epoxy. An adhesive standoff layer operates to contain the conductive material atop the transducer and enables attachment/adhesion between the flexible printed circuit and the transducer. As the adhesive layer is cured the pad electrode of the flexible printed circuit is drawn towards the transducer compressing the conductive material and causing it to flow to any open area on the transducers upper surface. Under ideal circumstances, the compressed conductive material provides a broad contact surface for the pad electrode ensuring an optimal electrical connection between the electrode and the transducer. However, in the real world, ideal circumstances are not always present.